The lung consists of five lobes. The left lung has a superior and inferior lobe, while the right lung has superior, middle, and inferior lobes. Thin walls of tissue called fissures separate the different lobes.

The superior lobes of each lung are the uppermost pieces, also called the upper lobes. Each lobe receives air from its own branch of the bronchial tree, called lobar (or secondary) bronchi. Within the lungs, these bronchi are divided into smaller tubes. The smallest of these tubes is called a bronchiole. Bronchioles control the exchange of gases with the alveoli, the tiny air sacs within the lungs.

Each lobe of the lungs has the same function: delivering oxygen into the bloodstream and removing carbon dioxide. Sections of lobe or entire lobes can be removed as a treatment for conditions such as lung cancer, tuberculosis, and emphysema.